Rocks & Minerals — Set 3
Geography · चट्टानें और खनिज · Questions 21–30 of 50
Which rock forms from the evaporation of saline water?
Correct Answer: A. Halite (Rock Salt)
Halite, or rock salt, is a chemical sedimentary rock formed by the evaporation of salty water. It is commonly found in dried lake beds or restricted marine basins. It is the mineral form of sodium chloride.
The parallel arrangement of minerals in metamorphic rocks is known as?
Correct Answer: D. Foliation
Foliation refers to the repetitive layering in metamorphic rocks caused by pressure. Examples of foliated rocks include slate, schist, and gneiss. Non-foliated rocks, like marble, do not show this layering.
Which metamorphic rock is characterized by distinct alternating light and dark bands?
Correct Answer: D. Gneiss
Gneiss is a high-grade metamorphic rock identified by its banded texture. The bands are formed by the segregation of light and dark minerals under high heat and pressure. It often forms from the metamorphism of granite or schist.
Which of the following is NOT a requirement for a substance to be defined as a mineral?
Correct Answer: A. Organic in origin
By scientific definition, minerals must be inorganic, meaning they are not formed from living things. They must also be naturally occurring solids with a crystal structure. Organic substances like coal are generally considered rocks, not minerals.
What is the process of turning loose sediment into solid rock called?
Correct Answer: C. Lithification
Lithification is the process that converts sediments into solid rock. It involves compaction (squeezing) and cementation (binding by minerals). This process creates sedimentary rocks.
Frost action breaking rocks apart is an example of which process?
Correct Answer: A. Mechanical Weathering
Mechanical (or physical) weathering physically breaks rocks into smaller pieces without changing their chemical composition. Frost action occurs when water freezes in cracks and expands. This expansion forces the rock apart.
Rust forming on iron-rich rocks is an example of?
Correct Answer: A. Chemical Weathering
Rusting is a form of chemical weathering known as oxidation. Oxygen reacts with iron in the rock to form iron oxide (rust), weakening the rock. This process alters the chemical composition of the rock.
Chalk is a specific form of which sedimentary rock?
Correct Answer: A. Limestone
Chalk is a soft, white, porous form of limestone. It is composed of the microscopic shells of ancient marine organisms called coccolithophores. The White Cliffs of Dover are a famous example of chalk formations.
The continuous process by which rocks change from one type to another is called?
Correct Answer: B. Rock Cycle
The Rock Cycle describes the geological processes that transform rocks between igneous, sedimentary, and metamorphic forms. No rock on Earth is permanent; they are constantly recycled over millions of years. Processes include melting, cooling, erosion, and pressure.
The ratio of a mineral's weight to the weight of an equal volume of water is its?
Correct Answer: C. Specific Gravity
Specific Gravity is a measure of the density of a mineral compared to water. For example, if a mineral has a specific gravity of 3, it is three times heavier than water. This property helps geologists identify different minerals.